Production of ammonia.



I No Drawing.

UNITED STATES PATENT OFFICE.

FRITZ HABER, 01E KARLSRUHE, ROBERT LE BQSSIG-NOL, F liERLIN, GERMANY- ASSIGNORS TO BADISCHE ANILIN AND SODA 'FAIBRIK, OE LUDWIGSHAFEN-ON-THE- RHINE, GERMANY, A CORPORATION OF GERMANY.

PRODUCTION or AMMONIA.

Specification of Letters Patent.

Application flied July 1, 1910. Serial No. 569,961.

7 To all wlwm it may concern:

Be it knownthat we, FRITZ HABER, Ph. D.,

rofessor of chemistry, and ROBERT LE ossINoL, B. Sc., subjects, respectively, of the King of Prussia and the Kin of Eng land, residing, respectively, at arlsruhe and Berlin, Germany, have invented new and useful Improvements in the Production of Ammonia, of which thefollowing is a specification. v

For a long time the synthetical production from its elements of ammonia, which is of great importance both for industry and agriculture, has been considered one of the most importantproblems of chemical technology, but all eiforts in this direction have up to the present remained fruitless. It is true that it is known that nitrogen and hydrogen combine to form ammonia with the use of suitable catalytic agents, but, even when employing the best known catalytic agents, the yields of ammonia obtained are so small that even an analytical determination thereof presents difliculties. The reaction was consequently only of theoretical importance and a technical use thereof was not to be thought of. During his studies on the equilibrium of ammonia, Nernst carried out the reaction under pressures of from 50 to atmospheres in order to obtain measurable quantities of ammonia. When working in this manner and employing a very slow current of gas, the best concentration he obtained was scarcely 0.9 per cent. As

soon, however, as he increased the tempera ture to obtain a greater velocity of reaction and to enable the gases to be passed more quickly, the concentration fell considerably (of. Jost, U ber die Verwendung E i/nes E Zektm'schen Druclcofens bed Behandlw tg Chemz'scher Glez'ch'ge'wz'chtc, Dissertation, Berlin, 1908, pp. 23%). These results led Nernst to pass a very unfavorable opinion on the possibility of producing ammonia on a technical scale from its elements (of. i/nte'r alz'a, Zeitschm'ft fz'ir E'lektrochemz'e, 1907, p. 524

It has now been found that ammonia can be prepared on a technical scale directly from its elements when employing catalytic agents, if the reaction be carried out under very high pressures, for instance atabout 100 atmospheres, or preferably at from 150 to 250 atmospheres, or even higher.

Patented Oct. 17, 1911.

such concentration, for instance over 2 per i cent, as to permit of carrying out the reaction on a technical scale, while more active catalytic agents produce considerably more favorable results, andit is easily possible to increase the concentration of the ammonia to such a degree that itcan be separated out in the liquid form merely by the application of cold.

The process of our invention can be carried out in a suitable vessel which is capable of withstanding the very high pressure used, or an ordinary vessel can be employed, provided that it is surrounded by a cover capable of resisting the pressure. The catalytic agent is passed into the vessel and a mixture of or containing hydrogen and nitrogen is passed through with the aid ofa pump, and either the vessel or the gases which are being introduced or the catalytic agent or more than one of these single elements can be heated so as to produce or maintain the necessary temperature. The temperature at which the reaction can be carried out may vary considerably, for instance an incipient red heat may be used, although of course a temperature atrwhich decomposition of the ammonia takes place should not be employed.

The following example will serve to illustrate the nature of this invention, but we do not limit the invention in any way to the example given. Pass a mixture of one part of nitrogen with three parts of hydrogen at a temperature of from six hundred and fifty to seven hundred degrees centigrade, and at a pressure of two hundred atmospheres, with an hourly velocity of two hundred and fifty liters (measured at ordinary pressure), over iron which has. been producedzby the reduction of the purest commercial iron oxid and which occupies a space of twenty cubic centimeters. In this way a yield of two hundred and fifty grams of ammonia or hour per liter contact material can easily be obtained.

Now what we claim is 1. The process of producing ammonia by passing a mixture containing nitrogen'and hydrogen over a suitable catalytic agent at a pressure of exceeding 100 atmospheres.

' 2. The process of producing ammonia by passing a mixture containing nitrogen and- Hydrogen over a suitable catalytic agent at a pressure of between 150 and 250 atmospheres.

3. The process of producing ammonia by passing a mixture containing nitrogen and hydrogen over a suitable catalytic agent'at a pressure of exceeding atmos heres and causing the ammonia which is o tained to be separated directl in the liquid form.

4. The process 0 producing ammonia by lgassing a mixture containing nitrogen and ydrogen over a suitable catal tic agent at a pressure ofbetween an 250 atmospheresand causing the ammonia which is obtained to be separated directly in the liquid form;

r 5. The process for the production of ammonia by passing a mixture containing nicausing the ammonia which is obtained to be separated directly in the liquid form.

6. The process for the production of ammonia by passing a mixture containing three volumes of nitrogen and one volume of hydrogen over iron at a pressure offrom one hundred and fifty to two hundred and fifty atmospheres and causing the ammonia. which is obtained to be separated directly in the liquid form.

In testimony whereof We have hereunto set our hands in the presence of the subscribing witnesses.

FRITZ HABER. ROBERT LE ROSSIGNOL. Witnesses to the signature of F. Haber:

J. ALEC. LLOYD, ERNEST FRANCIS EHRHARDT. Witnesses to the signature of R. Le Rossignolz HENRY HAsPER, WOLDEMAR HAUP'I.v 

